Method or process of making hollow metal balls.



No. 861,403. PATENTED JULY so, 1907. 0. SPAHR,

METHOD OR PROCESS 0P MAKING HOLLOW METAL BALL'.

APPLICATION FILED AUG;17, 1 "906. 3

zsaxn'rs-snnn'r 1.

PATENTED JULY 30, 1907.

0. SPAHR. METHOD on mocass OF MAKING HOLLOW METAL BALLS.

APlLIUATION FILED AUG. 17, 1908.

2 SHEETS-SHEET 2.

Elm mom No. se1,4os.

" TE: STATES ATE 'o'r'ro SPAHR, or PHILADELPHIA, PENNSYLVANIA.

Specification of Letters Patent.

are

METHOD OR PROCESS MAKING HOLLOW METAL BALLS.

esteemed July 30, 1907.

Application filed August 17, 1906. Serial No. 381,008-

1 To all whom it may concern:

. aspec ificationi metal ball.

Prior to my invention it was old in the art to constru'ct hollow metal balls by rolling a disk of metal first I into hemispherical or cup form, the cup part 0? which i had the same'diameter as the completed ball and then rolling the outer edge of the cup inward until the ball was completed, these successive steps being effected through the agency of rotary dies. Such balls, however, when completed are open to the objection that on the final completion thereof during the 'process of turning in the edges of the cup there always results a surplus of metal so that the completed ball is not symmetrical. It was also old in the art to construct a hollowmetal ball from a rectangular-shaped plate of metal by forcing the same through a die in such manner as toturn the corners of the plate upward, thus forming a cylindrical cup having lateral and inwardly inclined edges, and afterwards closing theupper portion of the cup by successive steps due to pressure. Metal balls formed by this process are also open to the objection that the surplus of m tal which results from the completion of the ball at the open side of the cup makes the same non-symmetrical.

My invention overcom this objectionable feature and I am enabled to make a pressed metal ball the internal and external surfaces of which are absolutely concentric at all parts, thus providing a ball which is equally strong for all diameters thereof and is absolutely symmetrical. I accomplish this result through the agency of punches and dies so constructed and operated that a. disk or mass of metal to be operated upon is first caused to assume a hemispherical shape and then successive cylindrical shapes. I then cause the outer or open edge of the cylindrical part to be gradually thinned so that any longitudinal section thereof is of a wedge-like nature I then by successive steps cause the thin edge to be turned inward until'the mass of metal assumes a spheroidal shape; finally compressing the metal into a spherical shape with a limited projection of such metal extending beyond the outer surface of the sphere, which projection of metal is ultimately forced inward by pressure until the completed ball assumes the desired symmetry. in this way I am enabled to make a hollow ball which is absolutely symmetrical throughout every portionthereof.

For a full and clear understandmg of my invention, such as will enable others skilled in the art to construct and use the same, reference is had to the accompanying drawings, inwhich Figure l. is a plan vi w of a metal disk to be operated upon, and, Figs. 2 to 5 inclusive arc sectional views taken through the dies and the material as it is suc cessively subjected to the action of such dies, the punches for effecting the successive actions through the dies being shown in elevational view. Figs. 6 to 10 inclusive are sectional views taken through further successive forms of dies and their surrounding guiding sleeves, illustrating also in sectional view the successive conformation of the material being acted upon. Fig. 11 illustrates in sectional view. a completed ball: Fig. 12 is a side elevational view of such ball.

All of the drawings are mad"v to scale and are designed Y to make a hollow metallic ball having an exterior diameter of 1} inches and an interior diameter of 1 inch.

Referring now to the drawings in detail and first to Figs. 1 to 4 inclusive, 1 represents the material to be .acted upon, shown in Fig. l as a metallic disk, preferably of steel and practically two and tlirce-eighths inches in diameter and one-eighth of an inch thick; 2 being cylindrical dies of the conformation shown, each successive die being of slightly-smaller diameter than its predecessor. 3 represents a punch having a hemispherical end and of cylindrical cross section, as shown in Figs. 2 and 3, and a similar end but of cone-shape as shown in Figs. 1 and 5; said dies being successively smaller as will be apparent on examination of the drawings.

After the metal is subjected to the action of the die 3 in Fig. 2 it assumes the hemisph rical shape illustrated by the number 4 and in position in Fig. 3 for the action of the punch in that figure, which action gives to the same the cylindrical conformation shown in Fig. 4 where it is now ready for the action of the first punch having a conical conformation, and when subjected to this action it assumes the conformation shown in Fig. 5, being gradually thinned at its upper edge. On forcing the punch 3 through the die 2 with the material in position as shown in Fig. 5, it is given the conformation shown in Fig. 6; that is to say, the upper edge is further thinned. It should be rcniarked in this connection that when metal of this nature, particularly steel, is subjected to such a process it becomes brittle and liable to crumble or break and, therefore, it is important that the material shall be placed in an annealing oven and subjected to any of the well known processes of annealing for-the purpose of putting it in condition to proceed with the process. I have ascertained in practice that ordinarily this annealing and rcannealing should be effected at about every third or l'ourth operation, but the operator will be governed by his judgment on examining the metal un'der treat exact diameter of the exterior diameter of the ball to be producedf The upper half of this die is of the conformationsliown and both of said halves are cylindrical exteriorly and lit accurately within a hollow cylin'r drical metal guiding sleeve Onforcing the 'dies 5' 1 5 and 6 together the material assumes the position shown in Fig. 8 where it is again subjected to the action of an additional pairol dies 5 and 6, the lower one of which is'the duplicate of the lower die shown in Fig. 6, the ripper die having the conformation shown and adapted I when the two dies are forced together to give to the 'materialthe conformation shown in Fig. 9, in which there is substituted for the die 6 oi Fig. 8 a die of the conlormatioushown having a centrally located opening so arranged that when the dies are compressed still '25 lurthcr and their faces brought together the material assumes the conformation shown in Fig. 10, the dies being now closed face to'l'ace; while there results an upwardly extending metallic neck as illustrated; An additional cylindrical male die 8 provided at its lower end with a curvature corresponding with the curvature of the exterior of the ball isnow inserted and forced downward until the upper end is flush with the upper end of the die 6, thereby causing the material to be firmly set or united together so that the ball is complcted and assumes the conformation shown in cross section inFig. l l, which it will be noted is absolutely symmetrical throughout. i 1

l have ascertained that a ball asthus constructed and especially when 'mad'eof good steel possesses 4 0 suflicient strength to meet with the requirements which are usually placed uponsolid steel balls, this being due to"the'lact of the entire symmetry thereof, both inside and out. 1

I do not limit the application of my processlolhe- 4 5 use of the special tools illustrated in the accompanying drawings, as obviously some f the features. thereof might be accomplished different devices. To illustrate, instead of thinning the upper edge of the hemispherical part by a cone-shaped die, as shown in Fig. 4 or" the drawings this thinning step might be effected by placing the cup in a turning lathe and turning it out or by turning the outer surface of the cylindrical part of the cup downward so as to give tothe mass of metal the same wedge-like shape incross section. Also the same result might be effected by subjecting the cylindrical portionpto the action of forging, mechanism of such peculiar construction as would give. the cup-like form shown in the drawings, my generic 4 invention being of such a nature that I believe I am '60 entitled broadly to the production of a metal ball or cup of ,hemispherical shape which is successively formed into a shol t cylinder or.cyliriders of differen ength, hemispheriral atgme end and then unwed down to leavea sufficient mass of metal such that when themetalisagain tumedjnward upon itself theamount parts thereof and having, therefore, like strength construed as of the most generic nature as to the method of operation and as to the resultant product, namely,

a hollow symmetrical metalball. v

Although I have described a novel process of making balls may be made from any metal which may be acted upon by dies and punches in the manner indieated, and I have ascertained that in the manufactured same process hereinbeiore described maybe effected,

condition of the metal as the process proceeds and being applicable in accordance with the best judgment of the operator. i

novel ball which results from the practice of the process hereinbelore described and. hereinafter claimed, as said ball is made,'in accordance with the requirement of i the Examiner, the subject matter of a divisional appli- -cation filed in the U. S. Patent Ofliee on the, 14th day of March, 1907, bearing Serial No. 362,280. Having thus described my invention what I claim and desire to 'secure'by Letters Patent of the United States is- 1. 'The descrlbed processof making a hollow metal ball, consisting in first fohmingn muss of metal rate a hemlter ol the hemisphere and lengthening the bo'dypart of the cup into a cylindrical form; then thlnning the body part thereof toward its outer edge and finally turning the thinned edge inward by successive bending and swaglng spherical shell of the same cross section throughout. v 2. The described process of making a hollow symmetrical metal ball, consisting in first compressing disk of metal by the successive application off-external pressure turning the thinned edge inward by successive-bending and swaglng spherical shell ofthe some cross sectlon' throughout, the materlal bel-ng subjected to an annealing; process-at various stages of the beforementloned stepfs. i

metal ball conslstlngfln subjecting a metnldlsk to pressure and lit-such monnr'asto form-ahemisphero, then by body pnrtof the hemisphere-and simultaneously reducing lts thickness toward the edge thereof; then subjecting-the Witnesses throughout all parts thereof, and my claims are to be a hollow symmetrical ball from sheet steel, I do notlimit myself to the use of such metal, as obviously such V such balls from different kinds of metal practically the the annealing steps being made dependent'upon the I make no claim in the present application to the.

spherical cup then simultaneously diminishing the dlume into the form of a hemisphere; then lengthenln'g ut the' body part thereof into a cylindrical form; then gradually thinning said body part toward its. outer edge nnd finally.

3-. The descrlbed process of making a symmetrical hollow thenppllcntlon offurther pressurerlengthenlngont the i y '120 some to an annealing process ithe ab? successlve foerldln'gedge inward lnto spheroidal Ltorrriiithen' agalnjnnnenllngy.

specification in the presence, of twosubscribing witnesses.

thereof shall he sufiicientto result 'in'a hollow metal 'l ball or sphere, absolutely symmetrical throughout allsteps until the mass assumes the form of'u symmetrical I 

